The Matrix makes no sense

"People are batteries for the machines." Um. Okay. So yes it's true
that people generate heat and electromagnetic impulses from their
brains, but that's only because they eat food.

Where does the food come from? There's no sunlight, so there's no
plants. The planet is nothing but detritus (cast-off waste and dead
things). So what are the machines feeding their people?

Worms? Insects? Fungi?

Why not use the worms/fungi as an energy source & just kill-off all the
people? Then Earth would be a machine planet, and no need for an
energy-expensive Matrix program.

:-)